• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.60-63
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• 2008

고에너지 물질의 상변화는 연소과정에서 발생하는 필연적으로 중요한 요소이다. 연소과정에서 발생한 고온, 고압의 가스는 주변의 물질과 상호작용을 통해 복잡한 현상을 일으키게 된다. 본 연구에서는 고에너지 물질의 상변화를 해석을 하기 위한 기초 연구로 상변화 변수를 이용하여, 증기 폭발을 해석하였다.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.23-29
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• 2018

The objective of this paper is to evaluate the reliability of a volute pump and presents test results through performance and life tests. The performance and life test methods were presented by analyzing the failure modes of the volute pump. Zero failure test time was calculated to evaluate the reliability of the volute pump and then, the test was performed under accelerated conditions. The test was also carried out to check the failure modes of the field conditions. This study can be provided to improve the product reliability through failure analysis of the volute pump. And failure cause of typical failure case has been investigated and improvement design has been presented. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the volute pump.

• 한국결정성장학회지
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• 제29권1호
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• pp.39-44
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• 2019

본 연구는 제품 개발에 있어 소재 선정은 수요자 중심의 니즈를 최대한 반영 할 수 있어야 한다는 중요성에 대하여, 'RE_Double Diamond' 디자인 프로세스를 새롭게 제안하였다. 또한, 기존 더블다이아몬드 방법론 중 공급자 중심의 2차 이해관계자 맵 프로세스를 적용하였으며, 시각화 중심의 정보구축을 포함하여 디자이너-엔지니어 간의 커뮤니케이션을 통한 소재의 선정에 대하여 보고하고자 한다.

• 한국세라믹학회지
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• 제55권3호
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• pp.224-229
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• 2018

OPC production requires high calorific value and emits a large amount of $CO_2$ through decarbonation of limestone, accounting for about 7% of $CO_2$ emissions. To reduce $CO_2$ emissions during the Ordinary Portland Cement (OPC) production process, there is a method of reducing the consumption of cement or lower temperature calcination for OPC product. In this study, for energy consumption reduction, we prepared Hauyne-belite cement by calcination at a low temperature compared to that used for OPC and studied the early hydration properties of the synthesized Hauyne-belite cement. We set the ratios of Hauyne and belite to 8 : 2, 5 : 5 and 3 : 7. For the hydration properties of the synthesized Hauyne-belite cement, we tested heat of hydration of paste and the compressive strength of mortar, using XRD and SEM for analysis of hydrates. As for our results, the temperature for optimum synthesis of Hauyne-belite is $1,250^{\circ}C$. Compressive strength of synthesized Hauyne-belite cement is lower than that of OPC, but it is confirmed that compressive strength of synthesized Hauyne-belite cement with mixing in of some other materials can be similar to that of OPC.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.311-317
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• 2007

"Environmentally Sound and Sustainable Development (ESSD)" is a key word in recent years. The construction industry, have put a great influence on ergonomic and sustainable environment. Recently, "green building certifications", such as Indoor Air Quality (IAQ) and eco-friendly material regulation have been established. With this regard, new construction and aged-housing remodeling projects are required to meet these certification criteria. Multi-housing residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Aged-housing remodeling project is very unique in that building residents are selected prior to design phase. Therefore, the analysis of resident's need for building materials in aged-housing remodeling is relatively easy compared to new building construction. As such, it is very important to analyze their preferences for eco-friendly materials prior to project execution. The purpose of this study is to find the needs of residents and priority of their needs. Based on their needs and priority, this paper provides a new strategy in using environment-friendly materials and maximizing their satisfaction level when aged housing remodeling is constructed. In addition, this paper provide new criteria in selecting new developed environmental materials in remodeling projects for the purpose of improving the safety and health level in construction industry.

• 한국세라믹학회지
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• 제31권10호
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• pp.1159-1168
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• 1994

We powders were synthesized from W powders in differnet particle sizes by Self-propagating High-temperature Synthesis process (SHS) using a chemical furnace. The effects of the mole ratio of chemical fuel content, pellet thickness and the mole ratio between carbon and tungsten (C/W Ratio) on synthesis were investigated with the tungsten powders have different particle size each other. Compositional and structural characterization of these powders was carried out by scanning electron microscope (SEM0 and x-ray diffractometer. Powder characterization was carried out by the measurement of particle size distribution with laser-particle size analyzer. The amounts of WC obtained by SHS process depend very much on the particle size of tungsten powder and heat contents given in a product, i.e. as the particle size of W powder is smaller, the amounts of WC produced increase. Also the more heat contents is given, the more amounts of WC increase. By optimizing the synthesis conditions, it is possible to fabricate WC powders which have little secondary phases (W2C, C).

• 한국의류산업학회지
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• 제23권6호
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• pp.781-789
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• 2021

To enhance the design and comfort of waist-protection corsets, this study analyzed the product characteristics of five types of posture-correction corsets that are available commercially. Additionally, subjective evaluation of the corsets was conducted on women aged 20 to 60 years, in terms of design, material preference, fit, comfort, degree of correction, freedom of movement, tightness, and convenience of front fastening. Following product analysis, the five corset types were divided into: two soft, one semi-hard, and two hard types in terms of the degree of elongation. As a result of pattern analysis, the soft type was designed to improve fit by reflecting the body curvature, whereas the semi-hard and hard types were relatively flat. Through the wearing sensation assessment, the hard type manufactured by company S was the best in terms of design, material, fit, comfort, correction degree, and freedom of movement. The soft type was average in design, material, and fit while relatively poor in the correction degree and tightness. The results indicated that soft materials, flexible bones with appropriate tension, patterns designed to snugly fit the body with large curvature at the top and bottom for better inflection, and adjustable support belts that can be double-fixed are crucial elements in improving the corset design to boost the comfort of wearing. These study results are helpful in the development of waist-protection corsets with excellent wearing comfort and design appreciated by customers.

• 청정기술
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• 제15권3호
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• pp.186-193
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• 2009

본 연구에서는 상용운전 중에 있는 반연속식 로터리 킬른형 열분해반응기에 지자체에서 발생되는 필름형 혼합 폐플라스틱을 투입한 후 열분해하여 얻은 저급의 열분해유를 세 형태의 반응온도 프로그램에서 분해반응시키고, 여기에서 얻어지는 생성유의 특성을 논의하였다. 원료인 저급 열분해유의 특성은 원소분석 및 발열량 분석, SIMDIST 분석으로 확인하였고, 각 반응온도 프로그램에 따른 분해반응 결과는 각 성분의 수율분포, 액상 생성물의 누적수율과 생성비 등으로 논의하였다. 연구결과는 한 단계 반응온도 프로그램에 비해 다단계 반응온도 프로그램의 경우가 원하는 생성물인 오일수율이 높았고, 상대적으로 잔류물의 수율은 낮게 나타났다. 연속적인 열분해반응에서 반응온도 프로그램은 생성물의 수율분포 등 생성유 특성에 많은 영향을 주었다.

• Design & Manufacturing
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• 제12권1호
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• pp.52-57
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• 2018

With the recent strengthening of environmental regulations and the need for cost reduction, excavators, a type of construction equipment, are being miniaturized while components are being developed in consideration of stability. In the case of excavator press parts, mainly high-strength steel sheets are being used to enhance stability and reduce weight. However, in the case of high-strength materials, there is a need to research product forming methods to reduce Springback in defects arising in parts assembly due to Springback that result from the internal residual stress that occurs in press forming being released after product forming. Accordingly, regarding the tank cover, an excavator press-forming part, this study selected a method to reduce distortion through analysis of the Springback occurrence rate and Springback causes through a forming analysis. A forming analysis was conducted for the Springback of the tank cover. Deformations of 13.714 mm in the upper part and 6.244 mm in the inner part of the product occurred, while wrinkles occurred on the sides of the product due to uneven thickness. A forming analysis was conducted for the major shapes of the product to investigate the causes of Springback. Distortion deformation due to the bead in the center of the product was confirmed to be a large factor. A Springback reduction method of correcting uneven thickness in the product sides, a Springback reduction method of removing the bead, and a correction method of restriking after the final forming were used in a forming analysis to determine the degree of Springback reduction. For the forming method to correct uneven thickness in the sides, deformation was reduced by 12% in the upper side compared to the existing model, but deformation in the inner side increased by 1%. For the restriking forming method, deformation decreased by 25% in the upper side and 13% in the inner side. For the bead removal method, deformation decreased by 28% in the upper side and 13% in the inner side, the largest Springback correction results. This indicates that the bead has a large affect on Springback.

• 소성∙가공
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• 제17권7호
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.